Right now a very limited number of people have a huge stake in how clinical trials turn out. Gambling markets open the field up for all kinds of people to make a bunch of money by interfering in the outcome

If a company with a drug in clinical trials is publicly traded, going long or short on shares of that company is functionally equivalent to a binary bet on the outcome. Stock in a biotech company that has a drug in clinical trials is equity with a pseudo embedded binary option which resolves when the trial results are announced. A stock can triple or fall by 2/3rds depending on the trial results.

Investors and speculators are already betting on the outcome of drug trials with hundreds of millions or billions of dollars in capital in public stock markets.